Ming-Yang Su
Naval Res. Lab. Detachment, SSC, MS 39529-5004
John Cartmill
Planning Systems, Inc., Slidell, LA 70458
In four ocean experiments conducted in 1985, 1991, and 1992, extensive
near-surface microbubble densities were obtained by both optical and acoustical
techniques. The bubble radius (r) range for the former is 8--200 (mu)m and the
range for the latter is 34--1200 (mu)m. Detailed analyses of the temporal
variations (both on the order of 10 and 60 s) of these bubble densities reveal
some common characteristics existing in all four sets of independent field
measurements. Two maxima appear in the bubble density with the first one near
r[sub 1]=100--150 (mu)m and the second one near r[sub 2]=20 (mu)m. The r[sub 1]
peak occurs immediately when a fresh breaking wave plume is generated near the
measuring sensor, while the r[sub 2] peak is more or less unchanged during the
entire measurement period. These two peaks essentially divide the bubble
density into two distinct radius ranges: the first range is 100